Application is made for purchase of an electron paramagnetic resonance (EPR) spectrometer to provide for enhanced spectroscopic capability for a Pennsylvania State University user's group in biological sciences. Existing equipment has been extensively used by a variety of laboratories over the past sixteen years, thereby establishing a pattern of novel applications ranging from analysis of metalloenzymes (or metallosubstrate enzyme complexes) to the physical analysis of the membranes and aqueous internal environment(s) of intact mammalian cells. This outmoded equipment, and its supplemental programs for computer analysis, should be replaced as its periodic failures now hinder completion of experiments and/or detailed analysis of the specta. Specifically, the six investigators forming the applicant group hold twelve currently funded federal research grants that utilize EPR spectroscopy. The topics include: (a) the use of water soluble spin labels to sample features of intracellular water, with applications ranging from relation of the cytoplasm to the stage of the cell cycle for many mammalian cell types to the effect of cryoprotectants on sperm cells; (b) the use of spin labels to assess unique perturbations of electron transport in sperm associated with binding of extracellular ligands to the sperm surface; (c) analysis of the lipid aspects of sperm membranes as related to the acquisition of fertility; and (d) determination of the spectroscopic features of metalloenzymes, including the Mn-nucleotide complexes of the substrates bound to ovine glutamine synthetase, Fe-complexes associated with fungal ligninase, and radicals associated with hydroperoxide formation. In summary, a minimum usage of greater than 60 hours per week is anticipated for this instrument. Receipt of this instrument will assure that these projects, in both biochemistry and cell biology, can continue.